Differential rebuild

[JonO]

The workshop manual asks you to use Tool 84B to obtain the size of the shim to give the required position of the pinion. I do not have Tool 84B. Can anyone advise the dimension between BDC of the Crownwheel carrier bearing supports to the front face of the pinion (or some other datum measurement) so I can set up the pinion correctly with the appropriate shims?

[flying farmer]

If you haven't binned the old bearing you can measure its thickness relative to that of the new bearing and calculate the required shim thickness from that. I have managed this a few times, even after grinding the old bearing off the pinion. Reassembling the remains with 4 rollers between the inner and outer race will do the job. I have found it a lot easier on saloon and TR diffs as Chris Witor can supply original Timken bearings for them, and dimensionally they are so close to the originals the bearings are normally a straight swap, unfortunately he doesn't list them for the Stag.
I am about to rebuild the diff of my Stag, I have got the bearings, just need to make a start
Neil

[JonO]

If you haven't binned the old bearing you can measure its thickness relative to that of the new bearing and calculate the required shim thickness from that. I have managed this a few times, even after grinding the old bearing off the pinion. Reassembling the remains with 4 rollers between the inner and outer race will do the job. I have found it a lot easier on saloon and TR diffs as Chris Witor can supply original Timken bearings for them, and dimensionally they are so close to the originals the bearings are normally a straight swap, unfortunately he doesn't list them for the Stag.
I am about to rebuild the diff of my Stag, I have got the bearings, just need to make a start
Neil

Thanks. I have new bearings from Rimmer Bros and I assume all 'equivalent' bearing dimension are within a thou or they wouldn't fit. On this assumption, my fall back position was simply to use the original shim. Have you experienced big differences in bearing dimensions? I still have all bearings intact and the bearing is still on the pinion.

[flying farmer]

If in doubt measure them all, crownwheel bearings as well. The inner and outer diameters will be right, but the thickness of the bearings may differ with different makes. The easiest way is to put the bearings old and new on a sheet of glass and put a steel ruler over the top. If they all measure the same using the old shims will be fine, if they are different then the diff will probably whine horribly if the differences are not accounted for. The rearmost pinion bearing is the most difficult one to deal with as once it is knocked onto the pinion you need a proper bearing puller to get it off again.
It is some years since I did a diff with non original bearings so I can't remember too much except it took several attempts to get it right, and the memory to measure first is still burned into my brain!
Neil

[Stagjag]

I had a problem with rimmer pinion bearings
Thay did not fit, so I took them to a bearing shop ,and thay managed
To find the same timken bearings and thay fitted like a glove

[pj-tigger]

The problem with the bearings is that the 78 parts book has the wrong part number (it lists 100897 as the pinion head bearing which is the one for the TR6 , T2000 etc) . The 74 parts manual list the corrct one - 152665.

For info the correct Timken Cup/Cone numbers for a Stag diff case are -

Pinion Head HM88610/HM88644
Pinion Tail M84510/M84548

If you have a TR6/T2000 case the numbers are

Pinion Head 3120/3188S
Pinion Tail 15245/15100SR

Interestingly if you pull the specs on the bearings the TR6/T2000 is a stronger bearing but the Stag ones are a smaller O/D and so give a thicker wall thickness on the diff case - i can only assume that the TR6/T2000 are over spec'd & the Triumph engineers decided that a thicker walled casing was preferential on the Stag ??

[elvimto]

I use a depth mic and a piece of 1 inch steel to get dimension from the top of the diff case to the top of the pinion. Lay the steel across the diff casing then use the depth mic to go to the top of the pinion shaft then subtract 1 inch. You should have no problem getting Timken bearings,you will have to do a final check with prussian blue to see where your are making contact and possibly make changes to get you in the right contact area. Good luck

cheers Stuart

[Westfaling]

Jon
This doc was posted previously and may be of help in your rebuild.
Nick